Phone contract help

To be honest I'm not entirely sure if this is in the right section so I apologize if it is.

I have 2 accounts with Verizon one for my personal phone and another for my family line phones.

My son used one of the numbers upgrades back in August to upgrade his line to a droid 4, then I myself now purchased a phone off amazon wireless using the upgrade for his line to buy a Nexus. Because I want to use it for my personal line that's separate from my family account. From what I've read once you activate the phone through amazon its stuck on that line? But if you take it into verizon before you do that you should be able to activate it for another line. My problem is I took it to verizon to do this. And the guy kept saying sorry can't do it. I have no clue what to do at this point.

Went to another verizon store and they activated it for me. But no line on either account got upgraded nothing changed and my original number I bought the phone for from amazon still says upgrade available. Also the number I have the Nexus on still shows upgrade available next this April.